How to create a two dimensional array from a stream in Java 8?

Question

I have a text file like this:

ids.txt

1000
999
745
123
...

I want to read this file and load it in a two dimension

Answer 1

Given a Stream you can parse each item to an int and wrap it into an Object[] using:

 strings
        .filter(s -> s.trim().length() > 0)
        .map(Integer::parseInt)
        .map(i -> new Object[]{i})

Now to turn that result into a Object[][] you can simply do:

Object[][] result = strings
        .filter(s -> s.trim().length() > 0)
        .map(Integer::parseInt)
        .map(i -> new Object[]{i})
        .toArray(Object[][]::new);

For the input:

final Stream strings = Stream.of("1000", "999", "745", "123");

Output:

[[1000], [999], [745], [123]]